Prelingual deafness greatly inhibits a child's natural acquisition of speech and may affect other communicative processes as well. Teaching a hearing-impaired child to communicate, whether through speech or through sign, is guided by our knowledge of development in the normal hearing child. One important aspect of normal language development is the acquisition of a set of communicative functions, or uses, of language for purposes of social interaction. The three broad objectives of this project are (a) to develop an instrument to assess early communicative functions that can be used with both normal hearing and hearing-impaired children; (b) to investigate factors of parent-child interaction that may have an influence on the H-I child's acquisition and use of the various functions; and (c) to develop teaching objectives and specific intervention strategies for children with hearing impairments. First, an appropriate taxonomy of functions will be developed, extending an existing scale that was used successfully in pilot work with very young children. The taxonomy and appropriate observational methodology will be incorporated into a scoring manual and training tape and then applied to a large sample of hearing children to obtain normative guidelines. Then the new instrument will be applied to samples of Oral-Aural and Total Communication hearing-impaired groups will compared to normal development and to one another. The project will then focus on discovering whether there are any significant relationships between features of hearing parent/deaf child communicative interactions and the child's expression of the various functions in the taxonomy. Finally, using knowledge obtained from the above, teaching objectives and specific intervention strategies will be developed to facilitate the acquisition of communicative functions and their transition to verbal expression.